Search results for " system"

showing 10 items of 57397 documents

Microstructure and electric properties of low-pressure plasma sprayed β-FeSi 2 based coatings

2017

Abstract Thermoelectric material β-FeSi 2 based coating was fabricated by the technique low-pressure plasma spray (LPPS) on the Al 2 O 3 substrate from different alloy powders. During the process LPPS, the phase transformation had occurred through the peritectoid, eutectoid reaction and their inverse reaction. The grain size of the as-sprayed β-FeSi 2 doped Co coatings was reduced comparing with the original feedstock powders, which implied the thermal conductivity could effectively decreased by the LPPS process. The room temperature electrical conductivity showed metal and semiconductor properties on the as-sprayed and annealed coatings. This method and the results could solve the problems…

010302 applied physicsMaterials scienceMetallurgyAlloy02 engineering and technologySurfaces and InterfacesGeneral Chemistryengineering.material021001 nanoscience & nanotechnologyCondensed Matter PhysicsThermoelectric materialsMicrostructure01 natural sciencesGrain sizeSurfaces Coatings and FilmsThermal conductivityCoating0103 physical sciencesMaterials ChemistryengineeringComposite material0210 nano-technologyThermal sprayingEutectic systemSurface and Coatings Technology
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Investigation of mechanical and electrical properties of Li doped sodium niobate ceramic system

2016

ABSTRACTThe Na0.96Li0.04NbO3 ceramic solid solution was prepared by means of a two-stage hot-pressing technology. The X-ray diffraction analysis showed the formation of a single perovskite phase with an orthorhombic symmetry in the investigated composition. The microstructure and EDS measurements were performed. They confirmed the high purity and the expected qualitative composition. A good homogeneity of the microstructures and a small degree of porosity were observed. The elastic modulus (the Young's modulus E, shear modulus G, and Poisson's ratio ν) of Na0.96Li0.04NbO3 were determined with the use of an ultrasonic method. The electrical properties of Na0.96Li0.04NbO3 ceramics were invest…

010302 applied physicsMaterials scienceModulusMineralogy02 engineering and technologyDielectric021001 nanoscience & nanotechnologyCondensed Matter PhysicsMicrostructure01 natural sciencesElectronic Optical and Magnetic MaterialsShear modulusControl and Systems Engineeringvisual_art0103 physical sciencesMaterials ChemistryCeramics and Compositesvisual_art.visual_art_mediumCeramicElectrical and Electronic EngineeringComposite material0210 nano-technologyPorosityElastic modulusSolid solutionIntegrated Ferroelectrics
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How Gettering Affects the Temperature Sensitivity of the Implied Open Circuit Voltage of Multicrystalline Silicon Wafers

2019

The temperature sensitivity of the open circuit voltage of a solar cell is mainly driven by changes in the intrinsic carrier concentration, but also by the temperature dependence of the limiting recombination mechanisms in the cell. This paper investigates the influence of recombination through metallic impurities on the temperature sensitivity of multicrystalline silicon wafers. Spatially resolved temperature dependent analysis is performed to evaluate the temperature sensitivity of wafers from different brick positions before and after being subjected to phosphorus diffusion gettering. Local spatial analysis is performed on intra-grain areas, dislocation clusters and grain boundaries. Lar…

010302 applied physicsMaterials scienceOpen-circuit voltagebusiness.industry02 engineering and technology021001 nanoscience & nanotechnology01 natural scienceslaw.inventionGetterlaw0103 physical sciencesSolar cellOptoelectronicsGrain boundaryWaferSensitivity (control systems)Dislocation0210 nano-technologybusinessRecombination2019 IEEE 46th Photovoltaic Specialists Conference (PVSC)
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Time-resolved pulsed OSL of ceramic YAP:Mn phosphors

2019

The paper deals with the results of comparative study on time-resolved pulsed optically stimulated luminescence (TR-OSL) response of ceramic YAP:Mn materials prepared by different methods. In parti...

010302 applied physicsMaterials scienceOptically stimulated luminescencebusiness.industryPhosphor02 engineering and technology021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesElectronic Optical and Magnetic MaterialsControl and Systems Engineeringvisual_art0103 physical sciencesThermoluminescent DosimetryMaterials ChemistryCeramics and Compositesvisual_art.visual_art_mediumOptoelectronicsCeramicElectrical and Electronic Engineering0210 nano-technologybusinessIntegrated Ferroelectrics
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X-ray and dielectric characterization of Co doped tetragonal BaTiO3 ceramics

2016

ABSTRACTThe crystal structure modifications of BaTiO3 induced by cobalt doping were studied. The polycrystalline (1 − x)BaTiO3 + xCo2O3 samples, with x ≤ 10 wt.%, were prepared by high temperature sintering conventional method. According to X-ray phase and structural characterization, performed by full-profile Rietveld refinement technique, all synthesized samples showed tetragonal symmetry perovskite structure with minor amount of parasitic phases. Pure single-phase composition has been detected only in the low level of doping BaTiO3. It was indicated that substitution of Co for the Ti sites in the (1 − x)BaTiO3 + xCo2O3 series led to decrease of tetragonality (c/a) of the BaTiO3 perovskit…

010302 applied physicsMaterials scienceRietveld refinementDopingchemistry.chemical_element02 engineering and technologyCrystal structureDielectric021001 nanoscience & nanotechnology01 natural scienceschemistry.chemical_compoundCrystallographyTetragonal crystal systemchemistry0103 physical sciencesBarium titanateGeneral Materials ScienceCrystallite0210 nano-technologyInstrumentationCobaltPhase Transitions
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Induced crystallographic changes in Cd1−xZnxO films grown on r-sapphire by AP-MOCVD: the effects of the Zn content when x ≤ 0.5

2020

High-resolution X-ray diffraction, scanning electron microscopy and transmission electron microscopy techniques were used to investigate, as a function of the nominal Zn content in the range of 0–50%, the out-of-plane and in-plane crystallographic characteristics of Cd1−xZnxO films grown on r-plane sapphire substrates via atmospheric pressure metal–organic chemical vapor deposition. The study is conducted to search for knowledge relating to the structural details during the transition process from a rock-salt to a wurtzite structure as the Zn content increases in this CdO–ZnO system. It has been found that it is possible to obtain films exhibiting a single (001) cubic orientation with good …

010302 applied physicsMaterials scienceScanning electron microscope02 engineering and technologyGeneral ChemistryChemical vapor deposition021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesCrystallographyTransmission electron microscopy0103 physical sciencesSapphireGeneral Materials ScienceOrthorhombic crystal systemCrystalliteMetalorganic vapour phase epitaxy0210 nano-technologyWurtzite crystal structureCrystEngComm
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Enhancement of the dielectric response through Al-substitution in La1.6Sr0.4NiO4 nickelates

2016

The structures and dielectric properties of La1.6Sr0.4Ni1−xAlxO4 (x = 0, 0.2 and 0.4) ceramics elaborated using the Pechini method were studied for the first time. The same unique tetragonal phase was found in all compounds. The lattice parameters were found using Rietveld refinement. The surface morphology characterization and elemental analysis of these samples were respectively carried out using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A giant dielectric response was observed in these ceramics, and one dielectric relaxation was found. The substitution of nickel with aluminum results in a colossal dielectric constant value (>106). The dielectric l…

010302 applied physicsMaterials scienceScanning electron microscopeRietveld refinementGeneral Chemical EngineeringAnalytical chemistrychemistry.chemical_elementMineralogy02 engineering and technologyGeneral ChemistryDielectric021001 nanoscience & nanotechnology01 natural sciencesTetragonal crystal systemNickelchemistryvisual_art0103 physical sciencesvisual_art.visual_art_mediumDielectric lossCeramic0210 nano-technologySpectroscopyRSC Advances
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Temperature Dependent Suns-V<inf>oc</inf> of Multicrystalline Silicon Solar Cells from Different Ingot Positions

2018

This paper presents temperature dependent Suns- Voc measurements on multicrystalline silicon cells originating from different ingot positions. The effective lifetime is found to increase for all cells when the temperature is increased from 25°C to 6°C. However, cells from the top of the ingot show a considerably larger increas 40–50% for illumination conditions of 0.1-1 Sun, compared to an increase of 20-30% observed for cells from the bottom. The decrease in Voc with increasing temperature is found to be lower for cells from the top of the ingot compared to cells from the bottom. The temperature coefficient of the Voc is found to vary 5% along the ingot at 1 Sun, highlighting the influence…

010302 applied physicsMaterials scienceSiliconbusiness.industry020209 energyPhotovoltaic systemchemistry.chemical_element02 engineering and technologySuns in alchemy01 natural sciencesTemperature measurementchemistry0103 physical sciences0202 electrical engineering electronic engineering information engineeringOptoelectronicsIngotbusinessTemperature coefficientSensitivity (electronics)2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC)
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Reduced temperature sensitivity of multicrystalline silicon solar cells with low ingot resistivity

2016

This study presents experimental data on the reduction of temperature sensitivity of multicrystalline silicon solar cells made from low resistivity ingot. The temperature coefficients of solar cells produced from different ingot resistivities are compared, and the advantages of increasing the net doping are explained.

010302 applied physicsMaterials scienceTemperature sensitivityintegumentary systemSiliconDopingMetallurgytechnology industry and agriculturefood and beverageschemistry.chemical_element02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesMonocrystalline siliconReduced propertieschemistryElectrical resistivity and conductivity0103 physical sciencesIngot0210 nano-technologySensitivity (electronics)2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)
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Partial discharge of gel insulated high voltage power modules subjected to unconventional voltage waveforms

2016

Performances and duration of the new generation of high voltage power electronic components are dependent on dielectric materials aim to insulating their internal terminals. The presence of defects, some due to faults generated during the manufacturing process, but also due to the internal design of layers and connections, can cause local enhancements of electric field and consequently possible activity of partial discharges phenomena or other effects (aging, tracking) that may result in reduction of device reliability. Furthermore, the usage of unconventional voltage waveforms, like square waves or pulse width modulated waves, additionally increases the electrical aging of the insulation s…

010302 applied physicsMaterials sciencebusiness.industryAcoustics020208 electrical & electronic engineeringElectrical engineeringHigh voltage02 engineering and technologyInsulated-gate bipolar transistor01 natural sciencesSettore ING-IND/31 - ElettrotecnicaReliability (semiconductor)Partial Discharge Gel insulation IGBTvisual_artInsulation systemPower module0103 physical sciencesElectronic componentPartial discharge0202 electrical engineering electronic engineering information engineeringvisual_art.visual_art_mediumbusinessVoltage2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)
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